NF-κB activity in perinatal brain during infectious and hypoxic-ischemic insults revealed by a reporter mouse

Anders Kielland1, Laura M A Camassa, Gaute Døhlen

  • 1Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Norway.

Insights

Newborn brain inflammation, a cause of lifelong impairment, was studied using a novel reporter mouse. This tool visualizes nuclear factor-kappa B (NF-κB) activation in vivo, revealing its role in perinatal brain injury models.

Area of Science:

  • Neuroscience
  • Immunology
  • Developmental Biology

Background:

  • Perinatal brain damage in infants, linked to infection or hypoxia-ischemia, causes lifelong impairments like cerebral palsy and cognitive disability.
  • Inflammation is a key contributor to perinatal brain damage, regardless of the initial cause.
  • Activation of the transcription factor nuclear factor-kappa B (NF-κB) is a central marker of inflammation.

Purpose of the Study:

  • To develop and utilize a transgenic reporter mouse for real-time imaging of NF-κB activity in the developing brain.
  • To investigate the role of NF-κB activation in experimental models of perinatal infection and hypoxia-ischemia.
  • To identify the specific cell types involved in NF-κB activation during perinatal brain injury.

Main Methods:

  • Development of a bidirectional transgenic reporter mouse with firefly luciferase and destabilized enhanced green fluorescent protein (dEGFP) under NF-κB control.
  • In vivo imaging of luciferase activity to monitor NF-κB activation in live newborn mice.
  • Ex vivo cellular-level detection of dEGFP expression in brain tissue sections to pinpoint NF-κB activation sites.

Main Results:

  • Increased luciferase signal in the brains of live mice subjected to infection or hypoxia-ischemia models, indicating elevated NF-κB activity.
  • dEGFP expression in brain sections confirmed NF-κB activation in endothelial cells of the blood-brain barrier across all disease models.
  • NF-κB activation was also observed in perivascular astrocytes in meningitis and hypoxia-ischemia models.

Conclusions:

  • The developed transgenic reporter mouse enables in vivo assessment of NF-κB activity during perinatal complications.
  • This tool allows for the precise determination of the cellular origins of inflammation in the brain.
  • Findings highlight the critical role of NF-κB in the inflammatory response to perinatal brain injury, offering potential therapeutic targets.